From: Peter Zijlstra <peterz@infradead.org>
To: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
x86@kernel.org, Borislav Petkov <bp@alien8.de>,
Josh Poimboeuf <jpoimboe@kernel.org>,
Babu Moger <babu.moger@amd.com>,
David.Kaplan@amd.com, Nikolay Borisov <nik.borisov@suse.com>,
gregkh@linuxfoundation.org, Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH RFC 4/4] x86/srso: Use CALL-based return thunks to reduce overhead
Date: Wed, 13 Sep 2023 15:17:16 +0200 [thread overview]
Message-ID: <20230913131716.GB22758@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <20230821112723.3995187-5-andrew.cooper3@citrix.com>
On Mon, Aug 21, 2023 at 12:27:23PM +0100, Andrew Cooper wrote:
>
> vmlinux.o: warning: objtool: srso_fam17_return_thunk(): can't find starting instruction
>
> @@ -288,26 +283,22 @@ SYM_START(srso_fam17_untrain_ret, SYM_L_GLOBAL, SYM_A_NONE)
> * and execution will continue at the return site read from the top of
> * the stack.
> */
> -SYM_INNER_LABEL(srso_fam17_safe_ret, SYM_L_GLOBAL)
> +SYM_INNER_LABEL(srso_fam17_return_thunk, SYM_L_GLOBAL)
This srso_safe_ret -> srso_fam17_safe_ret you forgot in the last patch,
is then here renamed yet again to srso_fam17_return_thunk.
And there is your objtool splat.
> + UNWIND_HINT_FUNC
> + ANNOTATE_NOENDBR
> lea 8(%_ASM_SP), %_ASM_SP
> + ANNOTATE_UNRET_SAFE
> ret
> int3
> int3
> /* end of movabs */
> lfence
> - call srso_fam17_safe_ret
> + call srso_fam17_return_thunk
> ud2
> -SYM_CODE_END(srso_fam17_safe_ret)
> +SYM_CODE_END(srso_fam17_return_thunk)
> SYM_FUNC_END(srso_fam17_untrain_ret)
> __EXPORT_THUNK(srso_fam17_untrain_ret)
>
prev parent reply other threads:[~2023-09-13 13:17 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-21 11:27 [PATCH 0/4] x86/srso: Reduce overhead of the mitigation Andrew Cooper
2023-08-21 11:27 ` [PATCH 1/4] x86/srso: Rename srso_alias_*() to srso_fam19_*() Andrew Cooper
2023-09-13 13:46 ` Borislav Petkov
2023-09-13 14:27 ` Andrew Cooper
2023-09-13 14:46 ` Borislav Petkov
2023-08-21 11:27 ` [PATCH 2/4] x86/srso: Rename fam17 SRSO infrastructure to srso_fam17_*() Andrew Cooper
2023-09-13 13:15 ` Peter Zijlstra
2023-08-21 11:27 ` [PATCH RFC 3/4] x86/ret-thunk: Support CALL-ing to the ret-thunk Andrew Cooper
2023-08-21 11:27 ` [PATCH RFC 4/4] x86/srso: Use CALL-based return thunks to reduce overhead Andrew Cooper
2023-08-21 15:16 ` Josh Poimboeuf
2023-08-21 23:01 ` Andrew Cooper
2023-08-22 2:22 ` Josh Poimboeuf
2023-08-22 6:45 ` Nikolay Borisov
2023-08-22 22:18 ` Josh Poimboeuf
2023-08-23 6:08 ` Nikolay Borisov
2023-09-13 12:50 ` Peter Zijlstra
2023-09-13 13:17 ` Peter Zijlstra [this message]
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